The invention relates to improvements in methods of and apparatus for regulating the operation of clutches and other types of torque transmission systems. More particularly, the invention relates to improvements in methods of and in apparatus for regulating the operation of torque transmission systems which are installed in power trains between prime movers and variable-speed or variable-ratio assemblies, such as between the clutches and the manual or automatic transmissions in the power trains of motor vehicles. Still more particularly, the invention relates to the transmission of torque between a prime mover (such as a combustion engine) and a variable-speed assembly (such as a manual transmission in the power train of a motor vehicle) by a system (such as a friction clutch) the operation of which can be regulated by an adjustable device in response to variations of the intensity and/or other characteristics of one or more signals.
It is often desirable to regulate the operation of torque transmission systems (such as various types of clutches including friction clutches and lockup or bypass clutches which are utilized in conjunction with hydrokinetic torque converters) in order to account for changes in the condition of one or more prime movers serving to supply torque to the torque transmission system, for changes in the condition and/or mode of operation of the assembly or assemblies receiving torque from the torque transmission system and/or for changes in the condition and/or mode of operation of the torque transmission systems, e.g., to account for the wear upon and/or for changes in the temperature of a torque transmission system including or constituting a friction clutch between the engine and the transmission in the power train of a motor vehicle. Proposals to carry out such regulation include the utilization of computer-controlled clutch managements which can influence the torque transmission system by way of a device known as actor.
Torque transmission systems which can be regulated in accordance with the present invention include, among others, various types of clutches which are designed in such a way that their rotary input and output members can slip relative to each other to a selected extent, i.e., that their input and output members can turn with reference to each other. Such slip can entail a more or less pronounced wear upon the abutting surfaces of the input (driving) and output (driven) members and the development of heat which involves a more or less pronounced thermal stressing of the torque transmission system. All of these factors must be taken into consideration if the torque transmission system is to operate satisfactorily for extended periods of time, e.g., during the useful life of a motor vehicle.
A proposal to regulate the operation of a torque transmission system between a prime mover and a variable-speed assembly is disclosed in published German patent application No. 36 24 008. This publication proposes to ascertain the friction performance of the torque transmission system and to generate a warning (alarm) or blocking (stoppage) signal in response to detection that the monitored friction performance exceeds a predetermined maximum permissible value. The thus obtained signal or signals can be utilized to eliminate and/or to otherwise influence the cause or causes of excessive friction performance.
In accordance with a proposal which is disclosed in the commonly owned U.S. Pat. No. 5,176,234, the torque transmission system (such as a friction clutch) is blocked when the magnitude of the monitored friction performance exceeds a preselected maximum permissible value.
All in all, heretofore known proposals to regulate the operation of a torque transmission system (such as a friction clutch) between a torque supplying prime mover (such as a combustion engine) and a torque receiving assembly (such as a manual transmission) in the power train of a motor vehicle involve the generation of an optical or acoustical signal which is transmitted to the operator of the motor vehicle embodying the torque transmission system or a certain adjustment of the torque transmission system, such as more pronounced engagement, full engagement, less pronounced engagement or full disengagement of a friction clutch.